A surface that is uniformly illuminated, with few or no bright or dim regions throughout the area illuminated, is visually attractive. When large in size, such a surface is likely to create a lasting impression on a viewer, and can be effective as a marketing or branding tool. In addition, uniformly illuminated surfaces can be useful in other applications such as x-ray viewers, etc.
As such surfaces increase in size, a number of lighting units may be required for complete illumination thereof. In such situations, uniform illumination of the surface can be difficult to achieve. Bright and/or dim regions are often present on the surface, thus decreasing the visual attractiveness and overall intended effect.
A number of solutions to the problems associated with providing uniform illumination of a large surface have been proposed. For example, in the past, High Intensity Discharge (HID) lighting units have been placed along the top and bottom of large surfaces in order to project light onto the surface. However, such systems do not provide uniform lighting of the surface, resulting in brighter regions near the top and bottom and dimmer regions towards the centre of the surface.
In addition, various lighting units, including fluorescent lighting units and Light Emitting Diodes (LED), have been used in combination with translucent surfaces in order to uniformly illuminate the surface. However, these methods of illumination can be very expensive to employ.
Similar problems are encountered in attempting to provide uniform lighting in general indoor and outdoor lighting applications.